During the last 5 years of support, we have identified genomic regions (quantitative trit loci, QTLs that contain some of the genes responsible to ethanol, including preference drinking, conditioned taste aversion, and acute an chronic withdrawal (section 3AC.1). An important goal of behavior genomics is to identify the gene underlying a QTL, and to elucidate the functional mechanism by which the gene influences the behavior of interest. In the next 5 years, complementary strategies will emphasize high resolution QTL mapping to approximately 1cm (Molecular Support Core, Component 2), and the identification of candidate genes within the QTL intervals. In the Molecular Genetics Support Core, the more promising candidate genes will be tested for differences in coding sequence (Component 3A) and expression/function (Component 3B) between appropriate animal models. Syntenic homology between mouse, human, and rat will be used together with the rapidly expanding gene/EST sequence and mapping databases to identify candidate genes/ESTs within the QTL intervals. Within the next five years, many genetic markers and almost all genes will be physically mapped in the human and mouse genomes. Consequently, knowing which genetic markers define a QTL region will automatically indicate which candidate genes are in the region. Priority for sequence and expression/function comparisons will be determined based on several criteria, including map location, putative biological role, likely relevance to ethanol action, and expression profile (e.g., known expression in the brain). Database sequence information will also be used to design oligonucleotide primers that flank genes of interest for polymerase chain reaction (PCR) amplification of the coding regions from both progenitor strains, and automated DNA sequencing of the PCR products will be carried out to identify possible sequence differences, with primary emphasis on protein coding regions. These PCR products will also be used as probes for candidate gene mRNA expression analyses (Component 3B). The Molecular Genetics Support Core involves all of the candidate gene cloning and sequencing needed for Components 4, 5, 6 and Pilot 10D. This Core Component also involves all of the expression analyses for Components 4, 6, and Pilot 10D. This Component will be active in all years of requested Center support.